SiO2-based nanofillers, commonly used to enhance the mechanical properties in tyres, favor a low hysteresis while maintaining sufficient reinforcement respect to the carbon black. However, a need remains to further reduce the rolling resistance of the tyres, and so to identify new fillers that allow a further improvement in the balance between hysteresis and reinforcement of materials. In this context, the present work aims at studying the self-assembly of two different white nanofillers, such as sepiolite and silica, and the role of collaborative filler network in rubber nanocomposites (NCs), considering that clay/silica hybrid systems could be a possible strategy to reduce the hysteresis of rubber materials, thanks to the potential synergistic effect between isotropic and anisotropic fillers.
Thus, rubber NCs containing silica and different kind of sepiolite were prepared by combining latex compounding technique (LCT) and melt blending. Highly filled NR masterbatches (MBs) were firstly prepared by coagulating natural rubber (NR) latex and sepiolite aqueous suspension, and then mixed with NR rubber matrix together with silica filler, silane coupling agent, vulcanizing agents, and antioxidants. An exhaustive morphological, rheological, and dynamic-mechanical analysis demonstrates that the use of double white fillers, having different aspect ratios, allows to obtain a good trade-off between efficient reinforcement and low Payne effect. These results have been ascribed to the formation of a cooperative filler network, deriving from the remarkable interaction of both fillers with the polymer, as assessed by morphological and spectroscopic investigations.
This study, even if referred to clay/silica double fillers, provides clear evidence of the significant role of self-assembly of hybrid nanofillers to produce a collaborative filler network and thus advanced rubber materials.
Graduated in Chemistry in 2001 at University “La Sapienza” of Rome, she obtained the PhD in Inorganic Chemistry at University of Florence. After working as post-doctoral researcher at Politecnico of Milano and at University of Milano Bicocca (Unimib), in March 2015, she became Assistant Professor of Fundamentals of Chemical Technologies at Unimib. She is a member of PhD Council on Materials Science and Nanotechnology, PhD Program of University of Milano- Bicocca. She coordinates the activity research of PhD students of CORIMAV (Consortium for research on materials between Unimib and Pirelli) and is responsible and referent for the research activity involving Pirelli Tyre.
She has advanced background in design and development of nanocomposite, hybrid and smart materials. Her research interests are nanostructured oxides and organic-inorganic materials for environmental cleaning, and design and development of rubber composites. She co-authored more than 40 papers in peer-reviewed journals, 4 book chapters, 7 patents, and involved in many national and international research projects.